1. Field of the Invention
The present invention relates to a video encoding apparatus and method for replacing an original image with an inter-encoded image and intra-encoding the inter-encoded image to reduce a flicker occurring between the inter-encoding and the intra-encoding.
2. Description of the Related Art
In video encoding, there are intra-encoding using intra-frame prediction (used for I picture mainly) and inter-encoding using inter-frame prediction (used for P/B picture mainly). The intra-encoding and inter-encoding differ in prediction method from each other. Therefore, the distortion due to encoding differs between the intra-encoding and inter-encoding. When images are encoded in order of, for example, I→P→P→P→P→P→P→I→P, the flicker of an image occurs on a screen in P→I. A method for solving this problem is already proposed in “Adaptive Quantization control for Reducing Flicker of AVCH.264 Intra Frames,” FIT2004LJ-009. This method controls an encoding parameter such that the encoding distortion of an encoded I picture is nearest to the predictive encoding distortion of a to-be-encoded I picture. However, the above method contains a problem that the flicker of an image can reduce only a scene containing a little movement. Actually, the flicker occurs due to the scene which a screen pans or the difference between the encoding distortions of I picture and P/B picture even if the scene contains movement of some extent.
As described above, there is a problem that the flicker can be reduced for only a scene containing a little movement.
The present invention is to provide a video encoding apparatus and method for encoding an image to be intra-encoded by inter-encoding at first and encoding a decoded image of the inter-encoded image by intra-encoding again, to reduce a flicker in every scene as well as a scene containing a little movement.